1. Field of the Invention
The present invention relates to a road-curve mirror used and a movable body detecting system adapted for transmitting/receiving radio waves between a vehicle and a movable body such as a vehicle or a pedestrian, so that the reception side detects the presence of the transmission side.
2. Description of Background Art
Conventionally, there have been proposed various methods which allow an operated vehicle to detect another movable body such as a vehicle in the neighborhood thereof.
For example, Japanese Patent Laid-open No. Hei2216600 discloses a method, in which a vehicle with an on-board receiver detects the presence of another movable body by receiving, via the on-board receiver, alarm radio waves continuously transmitted from a transmitter mounted on the movable body.
Japanese Patent Laid-open No. Hei7-244800 discloses a method in which an on-board receiver having the basic configuration similar to that of the on-board receiver described as above is improved to decide whether or not the received alarm radio waves are necessary by referring to the operational state of the vehicle and to indicate information based on the necessary alarm radio waves.
When a reception side vehicle is located at a position where the vehicle is hidden from a sight of a transmission side vehicle by an obstacle such as a building, the above alarm radio waves fail to reach the reception side vehicle. In addition, even if the alarm radio waves reaches the reception side vehicle, the strength of the electric field thereof becomes weak to such a degree that the reception side vehicle cannot accurately detect the presence of the transmission side vehicle.
On a road where the visibility of a driver in one vehicle against another vehicle is poor by an obstacle which blocks the presence of another vehicle, a road-curve mirror is generally provided in order that the driver in the vehicle can visually perceive the presence of another vehicle hidden therefrom by the reflection of an image of another vehicle from the mirror. In this case, however, unless the vehicle comes close to the road-curve mirror to some extent, the driver in the vehicle cannot visually detect the presence of another vehicle, or the driver in the vehicle may fail to have a look of the road-curve mirror.